Muffler Assembly Including A Center Muffler And Two Satellite Mufflers

ABSTRACT

A muffler assembly includes first, second, and third mufflers. The first muffler includes a first housing and an X-pipe that is at least partially disposed within the first housing. The X-pipe has first and second inlets and first and second outlets that are all fluidly connected to one another. The first and second inlets receive exhaust gas from the engine. The second muffler includes a second housing and a first Y-pipe that is at least partially disposed therein. The first Y-pipe has a third inlet that receives exhaust gas from the first outlet, and third and fourth outlets. The third muffler includes a third housing and a second Y-pipe that is at least partially disposed therein. The second Y-pipe has a fourth inlet that receives exhaust gas from the second outlet, and fifth and sixth outlets. The first, second, and third housings are spaced apart from one another.

FIELD

The present disclosure relates to a muffler assembly for an exhaustsystem of an internal combustion engine, and more particularly to amuffler assembly including a central muffler having an X-pipe and twosatellite mufflers having Y-pipes.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

An internal combustion engine can generate a substantial amount ofcombustion noise, which is transferred through an exhaust system and isaudible as tailpipe noise. Mufflers are used within exhaust systems toreduce this noise and/or tune the exhaust sound characteristics so thatthe tailpipe noise has desired sound qualities. Tradeoffs betweenpackaging space, flow performance, and sound characteristics are oftenmade in the design of a muffler. The present disclosure provides amuffler that fits within limited space on a vehicle while providing adesired level of performance and desired sound characteristics.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In one aspect, the present disclosure provides a muffler assembly forreceiving exhaust gas from an engine of a vehicle that is adapted totravel along a surface. The muffler assembly includes a first muffler, asecond muffler, and a third muffler. The first muffler includes a firsthousing and an X-pipe. The X-pipe is at least partially disposed withinthe first housing. The X-pipe has a first inlet, a first outlet, asecond inlet, and a second outlet. The first and second inlets are eachadapted to receive exhaust gas from the engine. Each of the first andsecond inlets and first and second outlets are fluidly connected to oneanother. The second muffler includes a second housing and a firstY-pipe. The first Y-pipe is at least partially disposed within thesecond housing. The first Y-pipe has a third inlet, a third outlet, anda fourth outlet. The third inlet is adapted to receive exhaust gas fromthe first outlet. The third muffler includes a third housing and asecond Y-pipe. The second Y-pipe is at least partially disposed withinthe third housing. The second Y-pipe has a fourth inlet, a fifth outlet,and a sixth outlet. The fourth inlet is adapted to receive exhaust gasfrom the second outlet. Each of the first housing, the second housing,and the third housing are spaced apart from one another.

In another aspect, the present disclosure provides a muffler assemblyfor receiving exhaust gas from an engine of a vehicle that is adapted totravel along a surface. The muffler assembly includes a first muffler, asecond muffler, and a third muffler. The first muffler includes a firsthousing, a first outlet, and a second outlet. The first housing definesa first cavity. The second muffler is adapted to receive exhaust gasfrom the first muffler. The second muffler includes a second housing anda first Y-pipe. The second housing defines a second cavity into whichthe first Y-pipe is at least partially disposed. The first Y-pipeincludes a first neck. The first neck extends outwardly from a firstmain body of the first Y-pipe. The first neck has a first opening thatis in direct fluid communication with the second cavity. The thirdmuffler is adapted to receive exhaust gas from the first muffler. Thethird muffler includes a third housing and a second Y-pipe. The thirdhousing defines a third cavity into which the second Y-pipe is at leastpartially disposed. The second Y-pipe includes a second neck. The secondneck extends outwardly from a second main body of the second Y-pipe. Thesecond neck has a second opening that is in direct fluid communicationwith the third cavity.

In yet another aspect, the present disclosure provides a mufflerassembly for receiving exhaust gas from an engine of a vehicle that isadapted to travel along a surface. The muffler includes a first muffler,a second muffler, and a third muffler. The first muffler includes afirst housing defining a first cavity, and an X-pipe. The X-pipe is atleast partially disposed within the first cavity. The X-pipe has a firstinlet, a first outlet, a second inlet, and a second outlet. The firstand second inlets are each adapted to receive exhaust gas from theengine. Each of the first and second inlets and first and second outletsare fluidly connected to one another. The X-pipe includes a junction.The junction includes an aperture. The aperture is open to and in directfluid communication with the first cavity. The second muffler includes asecond housing defining a second cavity, a third inlet, a third outlet,and a fourth outlet. The third inlet is configured to receive exhaustgas from the first outlet. The third muffler includes a third housingdefining a third cavity, a fourth inlet, a fifth outlet, and a sixthoutlet. The fourth inlet is configured to receive exhaust gas from thesecond outlet.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a perspective view of an exhaust assembly including a mufflerassembly having a central muffler and two satellite mufflers accordingto the principles of the present disclosure;

FIGS. 2A-2B show an X-pipe of the central muffler of FIG. 1; FIG. 2A isa front view; FIG. 2B is a perspective view;

FIG. 3 is a top view of a Y-pipe of one of the satellite mufflers ofFIG. 1;

FIG. 4 is a back view of the exhaust assembly of FIG. 1; and

FIG. 5 is a top view of the exhaust assembly of FIG. 1.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

With reference to FIGS. 1-3, an exemplary exhaust assembly 10 for aninternal combustion engine (not shown) according to certain aspects ofthe present disclosure is provided. During operation of the engine, theexhaust assembly 10 may receive exhaust gas discharged from the engine.The exhaust gas may flow from the engine, through a pair of exhaustpipes 12. The exhaust pipes 12 may be directly connected to the engine.In various aspects, the exhaust pipes 12 may be disposed near frontwheels of the vehicle. The exhaust assembly 10 may be a dual-exhaustassembly. In various aspects, the pair of exhaust pipes 12 may receiveexhaust gas from separate cylinder banks of the engine.

The exhaust assembly 10 may be shaped to fit within a given spaceavailable on a vehicle (not shown). For example, the exhaust assembly 10may be shaped to fit around a space tire well of the vehicle and/orother components at or near an undercarriage of the vehicle. The exhaustassembly 10 may include a first exhaust device 14, and a second exhaustdevice 16, and a muffler assembly 18. During operation, the first andsecond exhaust devices 14, 16 may receive exhaust gas from the engineand discharge exhaust gas to the muffler assembly 18. The first andsecond exhaust devices 14, 16 may be gasoline particulate filters (GPF),diesel particulate filters (DPF), diesel oxidation catalysts (DOC), leanNOx traps (LNT), selective catalytic reduction devices (SCR), oracoustic devices, such as mufflers, by way of example. In one example,the first exhaust device 14 is a first GPF and the second exhaust device16 is a second GPF.

The muffler assembly 18 may include a first muffler 20, a second muffler22, and a third muffler 24. In various aspects, the first muffler 20 isreferred to as a central muffler and the second and third mufflers 22,24 are collectively referred to as satellite mufflers. The centralmuffler 20 and each of the satellite mufflers 22, 24 are packagedseparately so that each muffler can be remotely located with respect tothe other mufflers. Therefore, the each of the mufflers 20, 22, 24 canbe arranged around on the vehicle as needed to accommodate othercomponents and meet packaging requirements. In an alternative aspect,the muffler assembly may include a central muffler, a single satellitemuffler, and another satellite exhaust device.

The central muffler 20 may include a first housing 26 having a firstshell 28 and a pair of first end caps 30. The first end caps 30 may besealingly coupled to the first shell 28. The first shell 28 may have anoval-shaped cross section substantially perpendicular to a longitudinalaxis of the first shell 28. The first housing 26 may define a firstcavity 31. The first cavity 31 may be open and free of baffles orsub-cavities. In various alternative aspects, the first housing 26 maybe a different type of housing, such as a clam-formed shell.

The central muffler 20 may also include an X-pipe 32 that is at leastpartially disposed within the first cavity 31. The first end caps 30 mayinclude a plurality of apertures 34 (i.e., four apertures) through whichthe X-pipe 32 extends. The X-pipe 32 may be sealingly coupled to thefirst housing 26 at the first end caps 30.

The X-pipe 32 may include a first inlet 36, a second inlet 38, a firstoutlet 40, and a second outlet 42 (FIG. 2A). Each of the first andsecond inlets 36, 38 and the first and second outlets 40, 42 may befluidly connected to one another. In other embodiments, the firstmuffler 20 may include alternative pipe configurations that have twoinlets and two outlets that are all fluidly connected to one another.For example, the first muffler 20 can include an H-pipe (not shown).

The X-pipe 32 may also include a junction 44 having an aperture 46 (FIG.2A). The aperture 46 may be open to and in direct fluid communicationwith the first cavity 31. The aperture 46 may function as a Helmholtzresonator. More particularly, as exhaust gas flows from the first andsecond inlets 36, 38 to the first and second outlets 40, 42 through thejunction 44 during operation of the engine, sound waves may travelthrough the aperture 46 and into the first cavity 31, thereby reducingnoise. Except for the aperture 46, the X-pipe 32 may be imperforate.

The second muffler 22 may include a second housing 48. The secondhousing 48 may not share any walls with the first housing 26. The secondhousing 48 may have a second shell 50 and a pair of second end caps 52.The second end caps 52 may be sealingly coupled to the second shell 50.The second shell 50 may have an oval-shaped cross section substantiallyperpendicular to a longitudinal axis of the second shell 50. The secondhousing 48 may define a second cavity 54. The second cavity 54 may beopen and free of baffles or sub-cavities. In various alternativeaspects, the second housing 48 may be a different type of housing, suchas a clam-formed shell.

The second muffler 22 may also include a first Y-pipe 56 that is atleast partially disposed within the second cavity 54. The second endcaps 52 may include a plurality of apertures 58 (i.e., three apertures)through which the first Y-pipe 56 extends. The first Y-pipe 56 may besealingly coupled to the second housing 48 at the second end caps 52.

As best shown in FIG. 3, the first Y-pipe 56 may include a third inlet60, a third outlet 62, and a fourth outlet 64. The third inlet 60 andthe third and fourth outlets 62, 64 may be fluidly connected to oneanother. In other embodiments, the second muffler may includealternative pipe configurations that have one inlet and two outlets thatare fluidly connected to one another. For example, the second muffler 22can include a T-pipe or a V-pipe (not shown).

During operation, the third inlet 60 of the first Y-pipe 56 may receiveexhaust gas from the first outlet 40 of the X-pipe 32. The exhaust gasmay flow through a junction 66 in the first Y-pipe 56 and then be splitinto first and second streams. The first stream may flow through a firstpipe portion 68 and then the third outlet 62. The second stream may flowthrough a second pipe portion 70 and then the fourth outlet 64. Thefirst and second pipe portions 68, 70 may define first and secondlengths, respectively. The second length may be greater than the firstlength.

The first Y-pipe 56 may further include a first neck 72 extendingoutwardly from a first main body 74 of the first Y-pipe 56. Moreparticularly, the first neck 72 may extend from the second pipe portion70. The neck 72 may include a first opening 82 (FIG. 1). The firstopening 82 may be open to and in direct fluid communication with thesecond cavity 54. The first neck 72 with the first opening 82 mayfunction as a Helmholtz resonator. Therefore, during operation of theengine, soundwaves may travel through the neck 72 and into the secondcavity 54 to reduce noise when exhaust gas flows through the firstY-pipe 56. Except from the first opening 82, the first Y-pipe 56 may beimperforate.

The third muffler 24 may be similar to the second muffler 22. Thus, thethird muffler 24 may include a third housing 84 defining a third cavity86. The third housing 84 may not share any walls with the first housing26 or the second housing 48. The third cavity 86 may be open and free ofbaffles or sub-cavities. In various alternative aspects, the thirdhousing 84 may be a different type of housing, such as a clam-formedshell.

The third muffler 24 may further include a second Y-pipe 88 that is atleast partially disposed within the third cavity 86. The second Y-pipe88 may include a fourth inlet 90, a fifth outlet 92, and a sixth outlet94. The fourth inlet 90 and fifth and sixth outlets 92, 94 may befluidly connected to one another.

The fourth inlet 90 of the second Y-pipe 88 may receive exhaust gas fromthe second outlet 42 of the X-pipe 32 during operation of the engine.The exhaust gas may flow through a junction 96 of the second Y-pipe 88and into third and fourth pipe portions 98, 100. The second Y-pipe 88may further include a second neck 102 extending outwardly from a secondmain body 104 of the second Y-pipe 88. More particularly, the secondneck 102 may extend from the fourth pipe portion 100. The second neck102 may include a second opening 106 that is open to and in direct fluidcommunication with the third cavity 86 to function as a Helmholtzresonator as described above.

In various alternative aspects, the second and third muffler 22, 24 eachinclude a single inlet and a single outlet so that the exhaust assembly10 includes two total outlets. For example, the first and second Y-pipes56, 88 may be replaced with single-inlet/single-outlet pipes, eachhaving the Helmholtz resonator. Where each of the second and thirdmuffler 22, 24 includes a single outlet, the second muffler 22 includesa third outlet and the third muffler includes a fourth outlet. In yetother alternative aspects, one of the second and third muffler 22, 24includes a single inlet and a single outlet and the other of the secondand third muffler 22, 24 includes a single inlet and two outlets so thatthe exhaust assembly 10 includes three total outlets.

The muffler assembly 18 may include a plurality of additional pipes tofluidly connect the central muffler 20 to the satellite mufflers 22, 24,and to discharge exhaust gas from the satellite mufflers 22, 24. Themuffler assembly 18 may include a first intermediate pipe 108 thatextends between the first muffler 20 and the second muffler 22 and asecond intermediate pipe 110 that extends between the first muffler 20and the third muffler 24. The first intermediate pipe 108 may fluidlyconnect the first outlet 40 and the third inlet 60. The secondintermediate pipe 110 may fluidly connect the second outlet 42 and thefourth inlet 90. Each of the first and second intermediate pipes 108,110 may be straight (i.e., extend linearly) and have a substantiallycircular cross section.

The first and second intermediate pipes 108, 110 may be sealinglycoupled to the X-pipe 32 at a location outside of the first housing 26.Similarly, the first and second intermediate pipes 108, 110 may besealingly coupled to respective first and second Y-pipes 56, 88 atlocations outside of the respective second and third housings 48, 84.The first and second intermediate pipes 108, 110 may be at leastpartially disposed outside of the first, second, and third housings 26,48, 84. In various aspects, the first and second intermediate pipes 108,110 may be fully disposed outside of the first, second, and thirdhousings 26, 48, 84. However, in alternative aspects, the X-pipe 32 andfirst and second Y-pipes 56, 88 may be fully disposed within therespective cavities 31, 54, 86, the first and second intermediate pipesmay extend into the cavities 31, 54, 86.

The muffler assembly 18 may include four outlets where exhaust gas isdischarged from the vehicle. Thus, the muffler assembly 18 may include afirst exhaust outlet pipe 120, a second exhaust outlet pipe 122, a thirdexhaust outlet pipe 124, and a fourth exhaust outlet pipe 125. The firstexhaust outlet pipe 125 may be sealingly coupled to the first portion 68of the first Y-pipe 56. The second exhaust outlet pipe 122 may besealingly coupled to the second portion 70 of the first Y-pipe 56. Thethird exhaust outlet pipe 124 may be sealingly coupled to the third pipeportion 98 of the second Y-pipe 88. The fourth exhaust outlet pipe 125may be sealingly coupled to the fourth pipe portion 100 of the secondY-pipe 88. The second and fourth exhaust outlet pipes 122, 125 may belonger than the first and third exhaust outlet pipes 120, 124.

The exhaust assembly 10 may further include first and second E-valves126, 127 disposed downstream of the respective first and second Y-pipes56, 88. The first E-valve 126 may be disposed on the second exhaustoutlet pipe 122. The second E-valve 127 may be disposed on the fourthexhaust outlet pipe 125. The first and second E-valves 126, 127 mayalternatively be disposed on the first and third exhaust pipe portions120, 124, respectively. The first, second, third, and fourth exhaustoutlet pipes 120, 122, 124, 125 include respective seventh, eighth,ninth, and tenth outlets 128, 130, 132, 134.

The exhaust assembly 10 may further include a first muffler inlet pipe138 and a second muffler inlet pipe 140. The first muffler inlet pipe138 may fluidly connect the first exhaust device 14 with the centralmuffler 20, and more particularly the first inlet 36 of the X-pipe 32.The second muffler inlet pipe 140 may fluidly connect the second exhaustdevice 16 with central muffler 20, and more particularly with the secondinlet 38 of the X-pipe 32. Each of the first and second muffler inletpipes 138, 140 may include one or more curves to depending on therespective positions of the central muffler 20 and the first and secondexhaust devices 14, 16.

Referring to FIGS. 4-5, the exhaust assembly 10 may be included on avehicle (not shown) that is adapted to travel along a surface 160. Thevehicle may include a longitudinal axis 162 (FIG. 5). The longitudinalaxis 162 may extend between a front of the vehicle and a rear of thevehicle. The packaging of the exhaust assembly components (i.e., thefirst and second exhaust devices 14, 16, the central muffler 20, and thesatellite mufflers 22, 24) in multiple distinct housings allows thecomponents to be spaced to accommodate various other vehicle components.

FIG. 4 shows a rear view of the exhaust assembly 10 as it could beoriented on a vehicle. The components 14, 16, 20, 22, 24 may be disposedat two or more different heights with respect to the surface 160. Asused herein, the term “height” refers to a position along a verticalaxis 164 that extends perpendicular to the surface 160. The firstexhaust device 14 may be disposed at a first height 166, the secondexhaust device 16 may be disposed at a second height 168, the firstmuffler 20 may be disposed at a third height 170, the second muffler 22may be disposed at a fourth height 172, and the third muffler 24 may bedisposed at a fifth height 174. Each height 166, 168, 170, 172, 174 mayrefer to a distance between the surface 160 and a vertical center of therespective component 14, 16, 20, 22, 24.

The first and second exhaust devices 14, 16 may be disposed higher thanthe first, second and third mufflers 20, 22, 24. Therefore, the firstand second heights 166, 168 may each be greater than the third, fourth,and fifth heights 170, 172, 174. The central muffler 20 may be disposedhigher than the satellite mufflers 22, 24. Therefore, the third height170 may be greater than the fourth and fifth heights 172, 174. Thefourth and fifth heights 172, 174 may be substantially equal so that thesecond and third mufflers 22, 24 are disposed at the same verticalposition. However, in alternative embodiments, the fourth and fifthheights 172, 174 are not equal.

The seventh, eighth, ninth, and tenth outlets 128, 130, 132, 134 of thefirst, second, third, and fourth exhaust outlet pipes120, 122, 124, 125,respectively, may all be disposed at a sixth height 176. Thus, each ofthe exhaust outlet pipes 120, 122, 124, 125 may be disposed at the samedistance from the surface 160. The sixth height 176 may be the same asthe fourth and fifth heights 172, 174. The first and second intermediatepipes 108, 110 may each be disposed at a seventh height 178. The firstand second intermediate pipes 108, 110 may extend substantially parallelto one another and to the surface 160.

Referring to FIG. 5, a top view of the exhaust assembly 10, as it wouldbe oriented on a vehicle, is shown. The components 14, 16, 20, 22, 24may be disposed at different lateral positions. As used herein, the term“lateral” refers to a side-to-side position with respect to the vehicle(e.g., a position along a transverse axis 180 that extends perpendicularto the longitudinal axis 162 and the vertical axis 164). The firstmuffler 20 may be laterally centered with respect to the vehicle. Thus,the longitudinal axis 162 may extend through the first muffler 20.

The first and second exhaust devices 14, 16 may each be disposedoutboard of the central muffler 20 (i.e., lateral centers of the firstand second exhaust devices 14, 16 are disposed outboard of a lateralcenter of the first muffler 20). The first and second exhaust devices14, 16 may be disposed on opposite sides of the first muffler 20 (i.e.,on opposite sides of the longitudinal axis 162). A position of thesecond exhaust device 16 may be a mirror image of a position of thefirst exhaust device 14 about a longitudinal plane 182 that extendsperpendicular to the surface 160 and along the longitudinal axis 162.The first and second exhaust devices 14, 16 may therefore be disposedequidistant from the first muffler 20. Because the first muffler 20 islaterally centered, the first and second exhaust devices 14, 16 may alsobe disposed equidistant from the longitudinal plane 182. In variousalternative aspects, however, the first muffler 20 may be disposedlaterally off center and/or laterally closer to one of the secondmuffler 22 and the third muffler 24.

The second and third mufflers 22, 24 may be disposed laterally outboardof the first muffler 20 (i.e., lateral centers of the second and thirdmufflers 22, 24 may be disposed outboard of the lateral center of thefirst muffler 20). The second and third mufflers 22, 24 may be disposedon opposite sides of the first muffler 20. A position of the secondmuffler 22 may be a mirror image of a position of the third muffler 24about the longitudinal plane 182 so that the second and third mufflers22, 24 are disposed laterally equidistant from the first muffler 20.

The second and third mufflers 22, 24 may also be disposed laterallyoutboard of the first and second exhaust devices 14, 16. Thus, the firstexhaust device 14 may be disposed laterally between the first muffler 20and the second muffler 22. The second exhaust device 16 may be disposedlaterally between the first muffler 20 and the third muffler 24.

The first exhaust device 14 may extend along a first center axis 184.The second exhaust device 16 may extend along a second center axis 188.The first and second axes 184, 188 may extend substantially parallel tothe longitudinal axis 162 of the vehicle.

At least a portion of the second exhaust outlet pipe 122 may be disposedoutboard of the first exhaust outlet pipe 120. Similarly, at least aportion of the fourth exhaust outlet pipe 125 may be disposed outboardof the third exhaust outlet pipe 124.

The components 14, 16, 20, 22, 24 may also be disposed at differentlongitudinal positions (i.e., at different locations along thelongitudinal axis 162 of the vehicle). The first and second exhaustdevices 14, 16 may each be disposed forward of (i.e., closer to a frontof the vehicle) the first muffler 20, and more particularly, of a thirdcenter axis 192 of the first muffler 20. The second and third mufflers22, 24 may be disposed forward of the first muffler 20 (i.e., fourth andfifth center axes 194, 196 of the second and third mufflers 22, 24,respectively, may be disposed forward of the third center axis 192 ofthe first muffler 20). However, in various alternative aspects, thefirst, second, and third mufflers 20, 22, 24 may be disposed at the samelongitudinal position. The third, fourth, and fifth center axes 192,194, 196 may each extend parallel to the transverse axis 180.

The seventh and ninth outlets 128, 132 of the first and third exhaustoutlet pipes 120, 124 may be disposed rearward of the eighth and tenth130, 134 outlets of the second and fourth exhaust outlet pipes 122, 125,respectively. The seventh and ninth outlets 128, 132 may be disposed atsubstantially the same longitudinal position. The eighth and tenthoutlets 130, 134 may be disposed at substantially the same longitudinalposition. The seventh, eighth, ninth, and tenth outlets 128, 130, 132,134 may each be oriented toward the rear of the vehicle so that exhaustis expelled from the rear of the vehicle and away from the vehicle.

Returning to FIGS. 1-2B, the X-pipe 32 may define a center plane 198that extends through each of the first and second inlets 36, 38 and thefirst and second outlets 40, 42. The first and second outlets 40, 42 maybe disposed below the first and second inlets 36, 38 (i.e., closer tothe surface than the first and second inlets 36, 38). More particularly,the center plane 198 may extend through centers of the first and secondinlets 36, 38 and first and second outlets 40, 42. The center plane 198may extend perpendicular to the longitudinal axis 162 of the vehicle andthrough the third center axis 192 of the first muffler 20. Thus, thecenter plane 198 may also extend substantially perpendicular to thesurface 160. The aperture 46 forming the Helmholz resonator may opentoward the front of the vehicle.

With reference to FIGS. 1 and 3, the second pipe portion 70 of the firstY-pipe 56 may be disposed forward of the first pipe portion 68. Thefourth pipe portion 100 of the second Y-pipe 88 may be disposed forwardof the third pipe portion 98. The first Y-pipe 56 may be a mirror imageof the second Y-pipe 88 about the longitudinal plane 182.

The X-pipe 32 may generally be vertically oriented (i.e., having aheight that is greater than a width). The Y-pipes 56, 88 may generallybe horizontally oriented (i.e., having a width that is greater than aheight). Returning to FIG. 4, the first housing 26 of the first muffler20 may define a first vertical dimension 210 perpendicular to thesurface 160. The second and third housings 48, 84 of the second andthird mufflers, respectively, may each define a second verticaldimension 212 perpendicular to the surface 160. With reference to FIG.5, the first housing 26 of the first muffler 20 may define a firstlongitudinal dimension 214 parallel to the longitudinal axis 162 of thevehicle. The second and third housings 48, 84 may each define a secondlongitudinal dimension 216 parallel to the longitudinal axis 162 of thevehicle. The first vertical dimension 210 may be greater than the firstlongitudinal dimension to accommodate the vertical orientation of theX-pipe 32. The second vertical dimension 212 may be less than the secondlongitudinal dimension 216 to accommodate the horizontal orientation ofthe first and second Y-pipes 56, 88.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A muffler assembly for receiving exhaust gas froman engine of a vehicle adapted to travel along a surface, the mufflerassembly comprising: a first muffler including a first housing and anX-pipe that is at least partially disposed within the first housing, theX-pipe having a first inlet, a first outlet, a second inlet, and asecond outlet, the first and second inlets each being adapted to receiveexhaust gas from the engine, each of the first and second inlets andfirst and second outlets being fluidly connected to one another; asecond muffler including a second housing and a first Y-pipe that is atleast partially disposed within the second housing, the first Y-pipehaving a third inlet that is adapted to receive exhaust gas from thefirst outlet, a third outlet, and a fourth outlet; and a third mufflerincluding a third housing and a second Y-pipe that is at least partiallydisposed within the third housing, the second Y-pipe having a fourthinlet that is adapted to receive exhaust gas from the second outlet, afifth outlet, and a sixth outlet, wherein each of the first housing, thesecond housing, and the third housing are spaced apart from one another.2. The muffler assembly of claim 1, wherein the X-pipe includes ajunction that includes an aperture, the aperture being open to and indirect fluid communication with a first cavity that is defined by thefirst housing.
 3. The muffler assembly of claim 1, wherein: the firstY-pipe includes a first neck that extends outwardly from a first mainbody of the first Y-pipe, the first neck including a first opening thatis in direct fluid communication a second cavity of the second housing;and the second Y-pipe includes a second neck that extends outwardly forma second main body of the second Y-pipe, the second neck including asecond opening that is in direct fluid communication with a third cavityof the third housing.
 4. The muffler assembly of claim 1, wherein theX-pipe is laterally centered with respect to the vehicle.
 5. The mufflerassembly of claim 1, wherein the X-pipe is disposed equidistant betweenthe first Y-pipe and the second Y-pipe.
 6. The muffler assembly of claim1, wherein the second Y-pipe is a mirror image of the first Y-pipe. 7.The muffler assembly of claim 1, wherein: the X-pipe defines a centerplane that extends through the first inlet, the second inlet, the firstoutlet, and the second outlet; and the center plane extendssubstantially perpendicular to a longitudinal axis of the vehicle. 8.The muffler assembly of claim 7, wherein the first and second inlets aredisposed about the first and second outlets with respect to the surface.9. The muffler assembly of claim 1, further comprising: a firstintermediate pipe extending between the first outlet and the thirdinlet, the first intermediate pipe being disposed at least partiallyoutside of the first housing and the second housing; and a secondintermediate pipe extending between the second outlet and the fourthinlet, the second intermediate pipe being at least partially disposedoutside of the first housing and the third housing.
 10. The mufflerassembly of claim 9, wherein the first and second intermediate pipes areeach linear and extend parallel to the surface.
 11. A muffler assemblyfor receiving exhaust gas from an engine of a vehicle adapted to travelalong a surface, the muffler assembly comprising: a first mufflerincluding a first housing, a first outlet, and a second outlet, thefirst housing defining a first cavity; a second muffler adapted toreceive exhaust gas from the first muffler, the second muffler includinga second housing and a first Y-pipe, the second housing defining asecond cavity into which the first Y-pipe is at least partiallydisposed, the first Y-pipe including a first neck that extends outwardlyfrom a first main body of the first Y-pipe, the first neck having afirst opening that is in direct fluid communication with the secondcavity; and a third muffler adapted to receive exhaust gas from thefirst muffler, the third muffler including a third housing and a secondY-pipe, the third housing defining a third cavity into which the secondY-pipe is at least partially disposed, the second Y-pipe including asecond neck that extends outwardly from a second main body of the secondY-pipe, the second neck having a second opening that is in direct fluidcommunication with the third cavity.
 12. The muffler assembly of claim11, wherein: the first Y-pipe includes a third outlet, a fourth outlet,a first junction, a first pipe portion that extends between the firstjunction and the third outlet, and a second pipe portion that extendsbetween the first junction and the fourth outlet; the second Y-pipeincludes a fifth outlet, a sixth outlet, a second junction, a third pipeportion that extends between the second junction and the fifth outlet,and a fourth pipe portion that extends between the second junction andthe sixth outlet; the first and third pipe portions define a firstlength; and the second and fourth pipe portions define a second lengththat is greater than the first length.
 13. The muffler assembly of claim12, wherein the first neck extends from the second pipe portion and thesecond neck extends from the fourth pipe portion.
 14. The mufflerassembly of claim 11, further comprising a first E-valve disposeddownstream of the first Y-pipe and a second E-valve disposed downstreamof the second Y-pipe.
 15. The muffler assembly of claim 14, wherein thefirst E-valve is disposed outside of the second housing and the secondE-valve is disposed outside of the third housing.
 16. The mufflerassembly of claim 11, wherein the first muffler includes a X-pipeincluding a first inlet, a second inlet, the first outlet, and thesecond outlet, the first and second inlets and the first and secondoutlets being fluidly connected to one another, the X-pipe including ajunction that includes an aperture, the aperture being open to and indirect fluid communication with the first cavity.
 17. The mufflerassembly of claim 16, wherein the aperture opens toward a front of thevehicle.
 18. The muffler assembly of claim 16, wherein: the first Y-pipeis imperforate except for the first opening; the second Y-pipe isimperforate except for the second opening; and the X-pipe is imperforateexcept for the aperture.
 19. A muffler assembly for receiving exhaustgas from an engine of a vehicle adapted to travel along a surface, themuffler assembly comprising: a first muffler including a first housingdefining a first cavity, and an X-pipe that is at least partiallydisposed within the first cavity, the X-pipe having a first inlet, afirst outlet, a second inlet, and a second outlet, the first and secondinlets each being adapted to receive exhaust gas from the engine, eachof the first and second inlets and first and second outlets beingfluidly connected to one another, the X-pipe including a junction thatincludes an aperture, the aperture being open to and in direct fluidcommunication with the first cavity; a second muffler including a secondhousing defining a second cavity, a third inlet configured to receiveexhaust gas from the first outlet, a third outlet, and a fourth outlet;and a third muffler including a third housing defining a third cavity, afourth inlet configured to receive exhaust gas from the second outlet, afifth outlet, and a sixth outlet.
 20. The muffler assembly of claim 19,wherein the aperture opens toward a front of the vehicle.